Vice President Joe Biden counseled President Obama to resist the military's call to add as many as 40,000 US forces to the campaign in Afghanistan in 2009, a new book reveals. Biden was unpersuaded by the rationale for doing so and called the request flawed.

According to the New York Post, the new book, Little America: The War Within the War for Afghanistan, claims that in planning the drawdown of troops two years later, the White House 'intentionally sidelined the CIA.'

Neither did President Obama read the CIA's assessment of Afghanistan that later found little benefit from the 30,000 'surge' forces he approved, the book quotes a US official as saying.

The book quotes from a previously undisclosed Biden memo to Obama in November 2009 that outlines his view that military commanders were asking the president to take a leap of faith by adding tens of thousands of forces whose role and mission were poorly defined.

Biden reportedly used a months-long White House review of the war to question how the same counterinsurgency strategy that had apparently worked in Iraq could be applied successfully to Afghanistan.

'I do not see how anyone who took part in our discussions could emerge without profound questions about the viability of counterinsurgency,' Biden wrote to Obama. In order to work, the counterinsurgency doctrine requires military gains to be paired with advances in government services, a credible Afghan government and Afghan security services that can take over, Biden's memo said.

The US military could accomplish any technical assignment, such as sweeping insurgents from a village, but 'no one can tell you with conviction when, and even if, we can produce the flip sides of the counter insurgency strategy,' Biden wrote. Instead the Vice President supported a buildup of 20,000, half the number requested by then-war commander General Stanley McChrystal.

The memo broadly echoed a secret message sent to Washington by the then-US Ambassador Karl Eikenberry who bluntly called Afghan President Hamid Karzai an unreliable partner for the proposed surge.

The president's compromise — adding 30,000 US forces and a deadline to begin bringing them home — blunted the momentum of a resurgent Taliban insurgency without committing the president to an open-ended war.